Jack for raising forms and flooring in erection of concrete buildings



March 23, 1954 w. F. FREDRICKSON r2,673,067 JACK FOR RAISINGF'ORMS AND FLOORING IN ERECTION OF CONCRETE BUILDINGS Filed May 7. 1951 4 Sheets-Sheet l @VMWW March 23, 1954 F. FREDRlcKsoN 2,673,067 JACK F'OR RAISING FORMS AND FLOORING IN ERECTION OF' CONCRETE BUILDINGS Filed May 7. 1951 4 Sheets-Sheet 2 rT-n March 23, 1954 W. JACK FOR RA IN ERECTIO Filed May 7, 1951 fig F. FREDRICKSON ISING FORMS AND FLOORING N OF' CONCRETE BUILDINGS 4 Sheets-Sheet 3 HrraP/yfy:

March 23, 1954 w. F. FREDRlcKsoN JACK FOR R ORMS A SING F' ND FLOORING IN ERECTION OF CONCRETE BUILDINGS 4 Sheets-Sheet 4 Filed May 7, 1951 Q www* Patented Mar. 23, 1954 JACKEOR'EAISING FORMS AND FLOORING 1N ERECTION or CONCRETE `BUILDINGS Wallace Fr Fredrickson signor, by mesneassi Minneapolis, Minn., asgnments, to VVMinot Builders Supply Co., Inc.,` acorporation of Minnesota Application May 7, 1951, Serial No. ,224;910

10 Claims. 1

Myfinventionrelatesto'ia jack for raisingforms and flooring in connection-1i with the erection of concrete buildingslsuch as concrete. elevators, wherein a jack rodwanchored in the concrete cooperates in connection with two setsiofisharp edged dogs engageable `'withtheirif sharp edges with the wall `of r the jack rod, in combination with means movable atrightangles' to the jack rodzwhich maywbeiop'erated pneumatically, hydraulically or electrically formoving the jack and the attached nooringand forms :upwardly a given amount atr each r impulse imparted to l it,` said movement being effected' by `the engagement of rollers with sloping surfaces :to gradually impart the lifting operationr o Heretofore it :has been proposed to have a .pneumatic lifting device l formed withan annularV chamber surrounding-` the `jack rod and movable vertically along the jack rod. `which is connected to the frame supporting the flooring and pouring forms. Pneumatic pressure isapplied directly to separate parts of ther lifting` device together with two sets of dogs, one of whichholds the frame tothe jack rod againstdownward `movement and permits upwardmovement, the other of which permits downward movement of the lifting memberi and preventsdownward movement of" the entire structure'. y

The sets of;` dogs. have been. fixed in various wayslwith a frame carrying the parts of the lft- I' ingr' member: andL in` practice i have* hadlltheir sharp edges held against theijack rod by tension spring means which have pulledJ the dogs into contact with the jack `rod.l`

The prior arrangement; `particularly as to the I" contact of the dogs with thewjackrodshas been very inefficient andwhashad `a frequent result of breaking or 'dullingz theirod engaginglsh'arpened edges of the dogs. A return towrelatively initial: position 'of the parts: of 1 the lifting device has been effected `in Vsome instances `by gravity and in other:` instances by tensionspring members, and this hasnot `been .very eifective for the purpose desired:

I have discovered an entirely new arrangement ofJ parts l of al jack `rod comprising upper and lower members wholly independent oneifrom the other, eachof:` which is adapted to `bemoved vertically alongthe jack rod, the `actual upper lifting member 'being moved vertically bypower means applied thereto, and the lower member being moved upwardly by tension: springs which have been distended during the raisinguofl the upperflifting members4 Y y The force which is applied `to the liftingwmember. for effecting vlifting action `operates atright angles to the jack rod. Itcomprises a slideposi-- tioned between theflowerpart` of the upper lifting' member and thelupper part of the lower lifting member, which slide has two parallel` parts between which'are jourrraled for free `rolling an upper set andra lower set o1 rollersfeachset of two rollers, which contact 'upwardly sloping cam members on `the'upper face of the lower lift-1 ing member; which cooperate with'theflower set of rollers and thrust the upper lifting member' and the" parts connected therewith l upwardly: aby cooperation of the Vrollers on the slide members; and which com-prisea similar setof downwardly sloping cam members on the-bottom face-oftheA upper lifting member, which permitsthessprings holding the ytwo lifting members ingeneral parallel relationto pull theflower lifting member into its initial position relative toi-the` upper,` lifting member.

The force is appliedto` the slide member from a i pneumatically `or hydraulically y Operated i pressure member directly. at'right y angles to the vertical extent of the .jack rod, or byelectric motors operating in thetsame way, by ,controlled electric current to operatefsuch motors.

The force-applying member is held byfoutwardly diverging links on the frame positioned between the lower face of the upper lifting member and the upper face of the lower lifting mem.

ber to hold the force-exerting part of the forceapplying member or the electric motor operation thereof so as to thrust directly in a line at right angles to the vertical extent of the jack rod.

It is a principal object offmy invention, therefore; to "provide two' lifting members which haver the jacklrod lextending vertically between them and which are entirely independent of eachother,`

except that the lower lifting mem-ber issuspendedi-through powerful-springs from the upperlifting member.

It is afurther object of` my invention to provide a slide between the twovlifting members having an upper set and a lower `set of rollers contacting cam guideways turned in opposite directions on the lower face of the upper lifting member and on the upper face ofthe lower lifting member respectively.

It is a further object of my invention to provide upper and lower sets of dogs* whichare relatively short and `eachof which-comprises two parts, a base part with* semi-cylindrical head which may befand is inlelfect freely pivoted to an: adjustable holderu having a pinin its head engaging in a socket in the cylindrical head? of the pin, and having a second member which has an outer curved sharp edge for engagement with the jack rod, said second member being removably held in rigid alignment upon the end of and by the head part of the dog. Each of said dogs is engaged by a compression spring held for adjustment upon a screw pin extending through the bottom face of the respective lifting members, each of said compression springs extending parallel with the jack rod and having engagement with a lower face of the dog close to the iack rod for direct thrust vertically upon the respective dogs to hold the sharp edges of the respective dogs in engagement with opposite sides of the jack rod, either to lock the lifting member against vertical movements relative to the dog or to permit said vertical movement.

It is a further object of my invention to pro- Vide the Slide member with a laterally extended end portion adapted to contact and be secured to a movable member forming in effect a thrust piston of the force-applying member.

It is a further object of my invention to provide a thrust-applying member which comprises a cylindrical chamber and a piston member closure therein, and which is freely supported by connection with the arm of the slide and by tivo sets of links outwardly diverging from each other, one set secured to the upper liftingr mem ber and the other set to the lower lifting inemw ber.

It is a further object of my invention in one form thereof to provide a source of compressed air having connection with the cylindrical cham-- ber of the thrust-applying member together with means for controlling the adjustment and escape of said compressed air operated either bv the hand of an operator or by automatic means for that purpose.

It is a further obiect of mv invention in am other form thereof to apply hvdraiilic pressure within the cylindrical chamber in the thrustapplvinfr member, such for example. as anv suitable oil. together with means either operated hv hand or automatically for releasine .snm nil to apply pressure at proper times and for thereafter effecting return of the nil to initial position through the force exerted by the springs .suspending the lower lifting member from the upper lifting member.

It is a further obiect of my invention to provide valve means subiect to the pressure from the pump which will automatically when the pump goes into action open pressure oil to the jack feed line and close pressure oil to the return line, together with means for restoring the valve member when the pump is stopped.

It is a further object of my invention to formv the slide member, which extends at substantially right angles to the vertical extent of the rod, of side plates. spaced apart and straddling the jack rod with two sets of cam-engaging rollers `iournaed in oppositely extending exten sions of said plates and with stop means carried between the plates and engageable with the jack rod at the end of any forward thrust movement of the slide.

The full objects and advantages of my invention will appear in connection with the specification hereinafter set out, and the novel features by which the advantageous and useful results are obtained will be particularly pointed out in the claims.

In the drawings illustrating an application of my invention in some of its forms:

Fig. 1 is an enlarged side elevation view partly in section of my novel jack arrangement.

Fig. 2 is a top plan view with the jack rod in section of what is shown in Fig. 1.

Fig. 3 is a sectional plan View taken on line 3-3 of Fig. 1.

Fig. 4 is a sectional plan view taken on line 1 -4 of Fig. 1, showing the manner of the sharpened edge of the dogs engaging the jack rod.

Fig. 5 is a sectional view taken on line 8 8 of Fig. 1.

Fig. 6 shows the position of a set of jacks and jack frames on a part of a concrete building being erected.

Fig. '7 shows the frame supporting the flooring and the concrete forms and the arrangement of my jack in reference to said frame.

Fig. 8 illustrates a body of compressed air adapted to be heated before delivery to the feed lines and jacks, together with a showing of the heating means for effecting such heating.

Fig. 9 is a sectional elevation view taken on line 9-9 of Fig. 1.

Fig. 10 is a sectional view taken substantially on line Iii-I of Fig. 1 showing the arrangement for attachment of the dogs.

Fig. 11 is an elevation View of the parts making up the oil pumping mechanism.

Fig. 12 is a sectional view through the flow control valve of the oil delivering mechanism.

Fig. 13 is a wiring diagram showing the manner in which the motor for forcing the oil is automatically electrically operated.

My jack comprises a top lifting member, designated generally as I0, and a bottom lifting member designated generally as II. These members are substantially identical in construction and comprise the following parts:

A top plate i2 for the upper lifting member IB, end plates I3 and I4, and a bottom plate I5 which it cut away, as indicated at I6,V to receive the jack rod il which is embedded in the concrete as it is poured and extends vertically therefrom in a well-known way. The top plate i2 of upper member I0 also is cut away at 32, as shown in Fig. 2 and in dotted lines in Fig. 1.

Similarly the lifting member II is provided with a top wall I8 and end walls I9 and 20, and a bottom wall 2l, cut away at 22 to receive the jack rod I'I. In lifting member II top wall I8 also is cut away.

At the front end of lifting member I0 is a flange 23 having thereon a hook 24 to which is connected a strong tension spring 25. The flange 23 has an enlarged portion 26 which has threaded therein a bolt 21 for a purpose later to be given.

Extending outwardly from the side of plate I3 of top member I0 is a flange 28 having thereon a' hook 29 to which is connected a spring 30; The flange 28 is made thick enough to receive the threaded bolt 3| for a purpose later to be pointed out.

Similarly the end plate has extending outwardly therefrom a short ange or lug 33 provided with a hook 34 to which the other end of spring is attached. Also threaded in lug 33 is a bolt 35 for a purpose later to be given. rEhe top wall i8 of lifting member I I is cut away, as indicated at 3G in Fig. 3 and in dotted lines in Fig. 1.

To end wall I9 of lower'lifting member lI is secured a flange 3'I,which is provided with a hoolr-` 38 to `which i the lowerv end of i spring 3l)l is attachedtii Also in flange31 there isthreadedra bo1t39 -for a purposelaterA to :be given.

Secured by-screws toan' enlargement 5I).r of `upper bar I2fof theliftingfmember louis a keeper plate140, as Ashown in-Figs. 'l and 2, which plate spans the.l opening `32forreceiving the` jack rod I1.` Similarlysecured byfscrewsfto ani-enlargement of upper plate I8 II isla keepenplate 415; asfshown in Fig. 1.

On the .lowerplate I5 ofthe upper lifting member 'I0 are apair `of flanges 42 and 43i'formed on opposite sides and incommonraxial plane ofthe jack` rod I1.- Theiflange 42-fis formedwith a sloping cam surface 44, andthe flange 43 is formed: with a corresponding sloping `camsurface 45. i Thesecam surfaces 44and45fareformed to be exactlyparallel.:

Similarly on the upper-bar I6of'lower:lifting member IIiare formed fianges 46 andi41 respectively on .opposite sides and along a common axial plane of jack rod I1.

On-fiange 46is `formed a sloping cam surface `48e', and` on" ange141- is formed a similar sloping cam surface 49. Cam surfacesx48 andi49 are partheir extremities `falli` allel andare positionediiso in common verticalpplanesfwith .camcsurfaces 45 and Y45 f respectively, slope downwardly Whi-lemcanri` surfaces 48 and `49 slope upwardly.

In the space between liftingmembers III` and `I I is located` a slide lmember lindicated generally by thereference-numeral 50,andshown inside elevation in Iigf-land-` in sectional iplan View in Fig. 3- The slide member comprises. two bars 5| and 52. spaced` apart; as shown in Fig. 3. Each ofthe bars, asshown inFig.1, comprises a central part 53 with an expanded front head 54 and a corresponding expanded rear head 55.

Shafts 56 and 51 are journaled in the upper parts of heads 54 and 55 and have thereon rollers 58'and 59, which rollers are held by contraction of springs 25 and 30 in contact with cam surfaces 44 and 45. In the lower parts of the heads `5I! and 55 are journaled shafts 60 and 6I upon which are mounted rollers 62 and 63, as shown in Fig. l.

From the above it will `be apparent that the slide member 55 iioats between liftingmembers III and II and` is heldiwith .the respective setsof rollers in contact with the beginnings .of the cam faces by the springs25 and 39. If, therefore,` the slide is moved from itsinitial position, as shown in Fig-1, tothe left, the contact of the sets of rollers upon the cam surfaces 44- and 45 and 48 and 49 separate the two lifting members I0 and II and i correspondingly .i extend the tension springs 25 and 30.

If, then, means are provided to permitmove.- ment only ofthe-upper lifting `memberllllgkthat memberjwillbe lifted .andltake with it 4theconnectedflooring and forms, lifting .them to the same extent that the upper lifting member I9 is moved upwardly.

At the same time.` the springs 25 and 30 will be extended and when the slide 50 is moved back to initial position, if theupperlifting memberis held stationary `the springs125and 30 will bring the lower lifting member Il into the position of Fig. l. This operation may be repeated as desired with the result of progressively lifting flooring and forms contacted by the upper lifting member III.

It is, of course,v necessary to anchor the `lower lifting-member'fto the jack rod while `the-upper lifting member is moved upwardly, alsoto'janchor. the.: =upperfvlift`irigA member to.r the "fjackfrod of lower lifting member when thesprings restore the lowerliftingmember to initial position. Thishas been donein various wayspin some instances by the useof sharp edged dogs engageable with their sharp edge at angles with `the jack rod and so held `as to beicapableV of sliding movements onithe jack rod when the upper `lifting memberis moved upwardly and con-.- versely when the springs move the lowerlifting member upwardly.

I have provided herein a radically new arrangement ofidogs and particularly the manner of holding them and producing the necessary pressure of the sharp edge against the jack rod.' Aswell shown in Fig; 1, in the first place vI arrange two diametrically` opposed dogs for` each lifting lmember which engages the jack rod with their sharpened edges ina horizontal plane'on each side of the jack rod.

In the` second place -I make the dogsvin two parts, a head part which is not subjectito wear, and a bit part which is removably secured to lthe head part and engages with itssharp edgeY the side of the jack. rodfand because it is subject to wear it must be frequently sharpened.

A third feature comprises holding the head member of the dogs by means which permit adjustmentto take care of grinding the bitparts of the dogs made necessary by `wear or use.

These dogs are all similar, as shown in- 1. In general the head parts 64,165, 66 and 14 will be exactly alike, each being provided i with` a socket 61 into which extends a pin 68 fastened on the end of screws 21, 3I, 39 and 35; however, head 14 is depicted substantially longer than heads 64, 65 andy 65 for a purpose which willfbe subsequently explained.

Secured by means of a pin 69 projecting from the centers of the heads (i4,` 65, 66. andi14 isa chisel or bit member 10 which has a curved, sharpened edge `1I adapted to engage andsbite into the substance of rod I1, there being for each lifting member I0 and I I two of said` bit members 16 in directly opposed relation, asshown in Fig. 1.

Plates 12 and 13 are secured to opposite sides of hea'd members 64, 65,-66 and 14 and receive between them the side walls of bitmemben 1I! and hold such members againstturning onthe pins 69.

AS shown inzFig 5, the bit members 19 and the heads 64, 65, 66 and 14 are square in Ycross section. As shown in the lower lefthand corner of Fig. l, heads 14 may be used which are very substantially longer than the headsw64, `65 and 65, which, of course, makes bit members 1.0 correspondingly shorter.

These longer heads, which maybe of varying lengths, are provided for substitution for shorter. head parts so that .the bit parts whichare necessarily formed ofspecial and .more expensive .steel may be vcontinuously. used until too short forfure' ther use'.` Also any of 65V and. 56,01 14, or like longer head parts,.ar'e adjustable through operation of screwbolts v21,- 3I, 35 and 39. i

The rounded end ofthe heads 15, as clearly shown in `Fig. 1, takes against theiinside wall 16 of top rail I2 of upper lifting member I5, or. the corresponding edge 11 of top rail I8 of the lower lifting member II. TheA screw bolts 21,f'3l and 35, and 39 may be individually operated .to move the dog members forwardly along these edges as the bit membersareA worn away at their sharp,-

ened edgesfromuse.

The angle? which the` combined dogs may have upper lifting memberlv IU;

the head parts such `as 64,

and 11 of the'lower lifting member II, is important and is maintained the same in all positions of adjustment of the dogs. This is accomplished in the following manner.

The bit members 'I9 have a wedge-shaped end, as shown in Fig. 1, and a curved biting edge 1I, as shown in Fig. 4. The lower surface 'I8 of these wedge-shaped ends is contacted by a compression or thrust spring 19, which is supported in each caseI upon screw members 8| extending through the upper surface 89 of the respective lower plates I5 of upper lifting member I9, and 2| of lower lifting member I I. The thrust of spring 'I9 is directly upon faces 'I8 of bit member 'I9 and that thrust is always such that when the curved edge 1| of the bit member 19 contacts a wall of the jack rod I1, as shown in Fig. 4, faces 19 and 89 will be parallel.

It will be noted that springs 19 have their thrust operating along lines parallel with the adjacent curved surface of the jack rod and close to the biting edge 1I of the bit members 59. The screw members 8| are threaded into a socket 92 and extend within the springs 19. By screwing these screw members 9| upwardly not only will the pressure of the spring 19 upon faces 'I8 of the wedge-shaped portion of the bit member 'I9 be regulated, but also the angle of the dogs to lower faces 16 of upper plate I2 of upper lifting member I9, and lower faces 'I1 of upper plate i8 of lower lifting member I I will remain constant, to hold all faces 19 of the bit members 'I9 and faces 89 of the plates in parallel relation.

As shown in Fig. l, the slide member 59 has each of its parts 5I and 52, and particularly its rear I:

head provided with rearwardly extending arms 83 and 84, respectively, as shown in Figs. l and 3. Each of the arms 83 and 84 is provided with a lip member 85 which is secured to a piston member 86 operative within a cylinder 81.

The cylinder 8'! is closed by a back wall 88 through which extends an opening 99 having connection with a pressure air hose 99 when the jack is operated pneumatically by compressed air. A rubber sealing member 9| is secured to the inner face of cylinder 86 andv is provided with an annular flange 92.

When, therefore, compressed air for pneumatic operation, or pressure oil for hydraulic operation, goes into the space back of the sealing member 9|, the operation of the piston is effected without possibility of Wastage of compressed air or pressure oil, since the pressure forces the flange 92 firmly against the inner wall of the cylinder.

The cylinder 81 and connected parts are supported by the bars 83 and 84 through the piston member 86.

A pair offupper links 94 and lower links 95 are provided, the upper links 94 being pivotally connected by bolt 95 with ear 91 extending outwardly from cylinder 81, and lower links 95 being pivoted upon bolt 98 extending through ear 99. The links 94 in turn are secured at their front ends to bplt |99 extending through flange member 28 heretofore described, and links 95 are pivotally secured by bolt I9| Vextending through flange member 31. The links 94 and 95 are shown outwardly diverging.

It will be seen that when compressed air or oil under pressure is introduced into chamber back of piston 88 the force of that operation will be transmitted to the slide 59 made up of the plates 5I and 52, and will move the slide and the rollers on it in contact with the respective sets of upper ydouble sets of transverse frame members cam surfaces 44 and 45,' and lower cam surfaces 48 and 49, with the result that the lifting members I9 and II must be pushed apart. And since the lower dogs 19 biting into the jack rod I1 will prevent any downward movement of lower lifting member II the effect will be to lift the upper lifting member I9 with all the parts connected to it and distend the tension springs 25 and 39.

When, therefore, the pressure in chamber is released the springs 25 and 39 will draw up the lower lifting member II, since the dogs 19 of the upper lifting member I9 will hold that against downward movement and the effect of this upward movement will be to cause the cam surfaces 44, 45 and 48, 49 acting upon rollers 58 and 59 and lower rollers 6| and 62 to transmit the force of distended springs 25 and 39, to restore the parts to initial position, as indicated in Fig. 1.

As shown in Fig. '7, a frame designated generally as II9 comprises a pair of vertical frame members |29 and I2I to both sides of which are bolted transverse spaced members |22 and I23. To this frame structure, the floor |99 and the form portions |24 and |25 are secured. Tizi;

I and |23 are spaced apart sufficiently to receive the jack rod I1 to which is secured the upper lifting member II and cylinder 81 of the jacks. The transverse frame members |22 rest upon the upper lifting member and as the jack is raised in the manner hereinbefore described the frame member IISI and the parts connected therewith will be elevated along the jack rod I'I.

Where air is employed to operate the jacks it will be compressed in a tank Figg, mounted on the floor I99 which is connected with frame members I I9 resting on the jacks about the` jack rods I1. In the practice of my invention the air will go from the tank |95 through a pipe |98 to an air heater |99 from which it goes through a feed line I I9 through branch lines I I I to the several jack cylinders 81 back of therubber sealing member 9 I, as shown in Fig. l.

'The heater |99 Fig. 8, may be conveniently formed with an outer casing I I2 which comprises upper air chambers II3 and II3' and a lower heat chamber I I4. Hot gasses will pass from heat generator |I5 through central passageway I I9 to discharge at top I I1. The air from pipe |98 must pass from chamber II3 to chamber II3 through a system of heated heat exchangers indicated generally at I I8. The air delivered to the jack cylinders 81 will, therefore, be heated to desired temperatures to prevent freezing of any water which may accumulate in the jack cylinders in case the apparatus is being used in freezing weather.

All of the springs 25 and 39 for all of the jacks which have been operated will then apply their force to pull up the lower jack member I I which through operation of rollers 59-59 and 52-63 will cause the slide 59 carrying said rollers to move back to the complete closing position shown in Fig. l, and then force is directly applied to the oil in the chamber back of the diaphragm 9i. This will result in literally forcing the oil that had been in the chambers to operate the jacks for the lifting operation back from the jacks and through the pipes I I I into the main lead pipe |42, and since the chamber |49 is then fully open, this will result in pushing the oil through opening I II I,

chamber I49, opening |48 and pipe |49 back into Y the tank.. l

As shown in the `wiring diagram of Fig. 13, line wires I-s and t |52 feed current tinto. the.- system. Whilethe closingofthefcircuit maybe `made by hand, thefpreferred form is to use a timing-switch indicated generally at |53.

' The `timing switch normally` breaks vthe circuit at |53. The switch|55 is controlled by asolenod |51. When switch `|53 is closed current will-'go from line lwire |5| through branch wires1|58 and |59 to one side ofy the solenoid and from branch wire. |60, through `pressure switch |32 and branch wirek |6|will go totheother` side of the solenoid which will` energize it and cause it to'close motor switchtIS. `This istrue because the pressure switch normally closes the circuit through it' from branchwire .|60 to branch wire |`6|.

When, however, :the pressure switch is` operatedr `to `be open,v the circuit toi the solenoid is open .and `the motor circuit` correspondingly opens, terminating operation :of the motor: This stops the pump. The spring i144 restoresthe valvezpiston 43 `to `initialpesition andthe. `oil isaforcedbackinto the tank` |26 as iabovedescribed.

i `-Theujacl-rs may also be operated hydraulically.

The means forcontrolling the delivery of oil are shown .inFigs l1,'12.andil3. Fig. llshowsthe general assembly, comprisinganloil tank |26 rfor receiving and `containing thezoil used inthe system, whichxpreferably `will `be a combined oil that `willY be `free-.flowing .even in very cold weatheru. From the tank |26 at its bottom leads a;pipe|21..which Yenters thechamber of a rotary pump |23` `at a point ,near its top. The pump is inline with the shaft |29 `of a motor |30 which maybe-an electric motor or a gas engine as desired. ..From:the.pump |28leads` a `pipe |3| which willbe ofithesame diameter asthe` inlet pipe |121 .and which is connected at it stop with a pressure.` switch |32.1- From aT :|,33` from pipe |L3|,a,pipe |34 leads through a T` |35 which connect with apressure-gage |36and from there the oil-goes through a vertical `pipe |31` into a valve memberw|38lwhich isshown in detail: infliig.` 12 andiwhich will now -be described.

@Thevalve member |338 has ;a cylindricalA `wall |39 and anfinner cylindrical chamberf|g40 which opens toward itsbottom through an opening|4| connected with the;` main oil delivery pipe l 42, which in turn connects all the pressurefpipes leading to the several jack cylinders 81.

t A valvepiston |43 is` slidably mounted within the cylinder chamber |40, and` is normallyfheld in its lowered position by a strong compression spring |44, which spring is heldforaction verticallylby` surrounding a pin., |45 extendingcentrally from a-closure plug I4|` whichcloses the upper end of chamber |40. Apsmall leak opening |41 will permit ilow of oil from the pumping line back into chamberV |40 when the spring p; |44 restores `the piston; `|43 to initial position, as shown in Fig..12. `Throughan opening |40 from chamber. |40 return oilwillflow throughpipe-MS into the top `of tank|2`6at |50.

,When, through electrical means hereinafter describedthe motor |30 is started,` pressureoil immediatelyforces the lpiston |43 up inchamber |340 to. uncover` opening |4| land block passage of oil toopening |48. 4That is `the `delivery position of the valve. The oil will thenfeedthrough the main feed `line |42 and branch lines linto the various cylindersA 81 causing all of thejacks simultaneously to push up the frameV member I 0 and connectedparts the smallgincrement of distanceprovided: in thesystem, which, inJ practice,

10 isusuallylthree-sixteenthsof an inch. The pressurerswitch |32 `will then cut` oilowof electricity Aandiresult in openingfthe motor` switch toistop the-motor.

As shownr inlFig. l there is anadjustable stop designated generally by the numeral .|62 which is. provided with five faces .to effect ve diierent lengths` of stop of therslidev50. These faces are designated respectively a., b, c, dvand e.

I'Asishown, .face a `is parallel with` the outer wall of the jack rod |1 which will permitzthe Alongest orsmaximumstroke of the slide .50. Faces b, c, dllandle'intthat ordercall for successive shorter strokes `of which the `strokestopped by face e isithe1shortest. These Vfaces are adaptedxto engage thewall of` the jack rod :|1, as indicated` in dotted lines at |63 which,of.;course, will limit the length `of that stroke.- The sloping facest44, 45.fortthe lower wall. of the uppermember, and 48 andi49 for the upper wall of the lower member, are long enough4 to accommodate the. throw,V for the :above indicated. ve distances.

The adjustable stop |62 is held by. a button member |64 extending through` theslide5l0. .In the button member |64 is a transverse slotr |65 adaptedto receiveA a screwdriver to turn `the member |62 `to .whatever position the work in hand `calls l for.

The longest throw .of the slide 50 willalso be stopped by the roller 163 .engaging adepression 5ta in the upright bar 501).

. :Theadvantages of .my inventionwill be .apparent from thev abovedescription, both in connection with( the means `of applying the force to theliIting members at right angles to. their-direction of movement andthe extent of the jack rod, and also for the `facti that it is `practicable with` this construction .to `useextremely tluidoil together with the,;practicalarrangement of the dogs shown, giving afar more eiective application of .force from .the pump `to the lifting means thanhas heretofore. been accomplished.

Furthermore the use of oil makes possible operating ithevlifting` jacks in heavy freezing weather, :which is not true whereaair is used since always there will be some condensation of water inthe jack cylinders `which will freeze the pistons and rendertthe entire apparatus` inoperative.

. VI claim:

`rl.l Arjack-for elevatingcforms in connection withl the` pouring `of concrete structures and` operative in connection-.fwith ajack` rodheld and imbedded inthe concrete, two independent liftingmembers surrounding andmovable along said jack; rod-.the lower face of one member and the upper face of the other member formed with `re-` spective sets of parallel sloping cam surfaces, and a slide `betweenthe members` having rollers` on opposite; sides thereoiengageable with said faces, andsprings` connecting the members tQhold the rollers in. contact with the faces.

3 2. Inycombinationzwith ajack rod, a jack comprising arst memberlenccmpassing thejack rod andvhavingf-spacedtop and bottom surfaces, a second imember encompasingihe jack` rod beneathethe first member and havingispaced top and bottom surfaces, the exterior `of the bottom surface of therst member Land the exterior surfaceof the top-`of4 .the second member` each formedvwith a slopingfcam surface, a laterally movable fdriven member positioned between said members ,and engaging the respective earn surfaces for verticallymovingone of saidamembers relative to ,the other--.'on;the,1 jack rod. tension springs Y; extending .-betweenrsaid members .and

forming a follow-up connection between the second member and the rst member, and a set of engaging dogs carried by each of said members beneath the top surface of said members, the dogs of the second member acting to hold said member in rigid relationship with the rod when the iirst member is moved and the set of dogs carried by the first member acting to hold said member rigid with respect to the rod when the springs move the second member relative to the iirst member.

3. In a jack of the class described in claim 2 in which each dog consists of a base portion adjustably secured to the respective member and a removable bit secured to said base portion at one end and having a sharpened rod engaging edge at its other end.

4. A device for elevating forms in connection with the pouring of concrete structures cooperating with a jack rod embedded in the concrete, comprising two independent lifting members movable along the jack rod, sloping cam surfaces formed on each of said lifting members, a laterally movable driven member positioned between said lifting members and engaging the respective cam surfaces for vertically moving one of said members relative to the other on the jack rod, and a pair of two part dogs connected with each lifting member, each do g having biting edges on one part arranged to engage the jack rod on opposite sides thereof.

5. In combination with a jack rod, a jack comprising a first member which encompasses the jack rod and has spaced top and bottom surfaces, a sloping cam surface which is formed exterior to the bottom surface of said first member, a second member which encompasses the jack rod beneath the first member and has spaced top and bottom surfaces, a second sloping cam surface which is formed exterior to the top surface of said second member, a laterally movable driven member positioned between said rst and second members and engaging the respective cam surfaces for vertically moving one of said members relative to the other on the jack rod, a pair of two part rod engaging dogs carried at an angle with said jack rod by each of said members between their top and bottom surfaces, adjustable means carried by both said rst and second members for` maintaining said two part dogs at a constant angle with the jack rod though the length of said dogs is variable, and tension springs extending between said first and second members and forming a follow-up connection between the second member and the first member.

6. A device for elevating forms in connection with the pouring of concrete structure and cooperating with a jack rod embedded in the concrete, comprising a first and a second hollow lifting member movable along said jack rod and positioned one above the other, a sloping cam surface formed on the bottom side of said first lifting member, a second sloping cam surface formed on the top side of said second lifting member, a laterally movable driven member positioned between said lifting members and engaging their respective cam surfaces for vertically moving one of said members relative to the other on the jack rod, tension springs extending between said lifting members and forming a follow-up connection between the second member and the rst member, a pair of two part dogs contained within the hollow portion of each of said lifting members and forming an angle with the jack rod, each dog consisting of one part having a cylindrical head with a socket formed in its outer extremity and the other part formed with a front biting edge to engage the jack rod, horizontally adjustable abutments carried by both lifting members and engageable in each of said sockets to move the dog horizontally to take up wear on the biting edge of the second part of each of said dogs, and adjustable spring means carried by both lifting members and cooperating with said adjustable abutments for maintaining the biting edge of the second part of each of said dogs at a constant angle with the jack rod, the pair of dogs carried by the second lifting member acting to hold said member in rigid relationship with the rod when the first member is moved and the pair of dogs carried by the rst lifting member acting to hold said member rigid with respect to the rod when the springs move the second member.

7. A jack for supporting and raising a lifting frame on a jack rod, comprising a first movable member encompassing the jack rod and provided with a lower surface, a second movable member encompassing the jack rod beneath the first member and provided with an upper surface, a set of rod engaging bits carried by each of said members and acting to hold the respective member on the jack rod during vrelative movement of the other member, means connectin;r said members and forming a resilient followup connection for moving the second member relative to the first member, a driven member positioned between the first and second members and adapted for intermittent lateral movement between the lower surface of the rst member and the upper surface of the second member and provided with two oppositely disposed surfaces which extend in opposition to the lower surface of the upper member and the upper surface of the lower member to thereby provide four opposing surfaces between the three members, at least two inclined planes formed on two of said four surfaces, and at least two roller members carried on the remaining two surfaces which cooperate with the inclined planes on the opposing surfaces to provide relative movement between the first and second members when the driven member is moved in one direction between l. said members.

8. A jacklfor supporting and raising a form on a jack. rod embodying a pair of relatively movable members encompassing the jack rod and spaced with relation to each other on the jack rod, means operating in the space between said members for intermittently moving one member relative to the other member, means connecting said members and forming a resilient follow-up connection for moving the other of said members between intermittent operations of said last named means, of rod engaging means for supporting at least one of said members on the jack rod during movement of the other member comprising a supporting head having an outer end and an inner end and whose axis extends at an angle with respect to the jack rod, a first adjusting means supported by said lifting member and journalled to the outer end of the head at one side of its axis to move the head relative to the jack rod while permitting the hea-d to maintain a constant angle with respect to the jack rod, a bit having an outer end bevelled on its opposite sides to a sharpened end edge for engaging the jack rod and an inner end conforming to the inner end of the head, means detachably connecting the inner end of 13 the bit to the inner end of the head, and a second adjusting means carrier by said lifting member and engaging one of the bevelled end portions of the bit for holding the sharpened end edge of the bit in engagement with the jack rod.

9. In a jack for supporting and raising a form on a jack rod, embodying a lifting member movable along said jack rod, in combination with said member of rod engaging means comprising a supporting head having an outer end and an inner end and whose axis extends at an angle with respect to the jack rod, a rst adjusting means supported by the lifting member and journalled to the outer end of the head at one side of its axis to move the head relative to the jack rod while permitting the head to maintain a constant angle With respect to the jack rod, a bit having an outer end bevelled on its opposite sides to a sharpened end edge for engaging the jack rod and an inner end conforming to the inner end of the head, means detachably connecting the inner end of the bit to the inner end of the head, and a second adjusting means carried by said lifting member and engaging one of the bevelled end portions of the bit for holding the sharpened end edge of the bit in engagement with the jack rod.

10. In a jack for supporting and raising a form on a jack rod, embodying a lifting member movable along said jack rod, in combination with said member of rod engaging means consisting of a supporting head having an outer end and an inner end Whose axis extends at an angle with respect to the jack rod, said head having a socket formed in its outer end on one side of the axis, an adjusting screw supported by said lifting member in a plane transverse to the jack rod and journalled at one end in the socket of said head, a bit having an outer end bevelled on two opposite sides to a sharpened end edge for engaging the jack rod and an inner end conforming to the inner end of the head, means detachably connecting the inner end of the bit to the inner end of the head Whereby the head and bit are movable relative to the jack rod while held at a constant angle with respect to the jack rod, a spring carried by said lifting member in a plane parallel with the jack rod and engaging one of the bevelled end portions of the bit adjacent the jack rod, and an adjusting screw carried by said lifting member and operatively connected to said spring for adjusting the tension on the outer end of the bit to maintain the sharpened end edge in contact with the jack rod.

WALLACE F. FREDRICKSON.

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